Polishing system based on the non-newton fluid and polishing method thereof

ABSTRACT

A polishing system based on a non-Newtonian fluid and a polishing method thereof are provided. The polishing system includes a polishing device, a non-Newtonian fluid auxiliary device and a control device. The polishing device is able to move a work piece in a polishing container containing the non-Newtonian fluid with abrasives that cause the polishing action. The non-Newtonian fluid auxiliary device is able to manipulate the viscosity of the non-Newtonian fluid by varying the pressure, speed, vibration or ultrasonic frequency, which causes the abrasives to polish the work piece. The control device is used to optimize the polishing process by controlling how the polishing device moves the work piece inside the polishing container. In this way, by using the polishing method, the polishing system provided is able to polish a work piece with any three-dimensional shape.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Taiwan Patent Application No. 104126857, filed on Aug. 18, 2015 in the Taiwan Intellectual Property Office, the content of which is hereby incorporated by reference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polishing system and the polishing method thereof, especially a polishing system based on a non-Newtonian fluid and the polishing method thereof.

2. Description of the Related Art

As the manufacturing industry and technology progress, products in various shapes need to have their surfaces polished, and the demand for high quality polishing of surfaces continues to increase. At the same time, there is a requirement for higher standard in process efficiency, cost control, and waste management. In particular, for those consumer products that become obsolete rapidly, in their manufacture the aim is to produce a high quality surface finish, while also maximizing the efficiency and minimizing the costs, in order to shorten the production cycle and maximize the overall cost-effectiveness.

Although the mechanical chemical polishing of prior art is efficient, the process is contact-type polishing which can not be applied to a work piece with 3-dimensional (3D) shape that is hard to reach, requiring instead a grinding tool (such as a polishing pad), which increases the cost. Besides, the process involves more factors that affect the product quality, so the process is hard to control. More importantly, a major limitation of this method of prior art is that vast amounts of waste fluid have to be processed.

The non-contact-type polishing of prior art, such as jet-polishing and magnetorheological polishing, generally deliver a very high quality of surface polish, and can theoretically process a work piece of any shape. However, in reality, these methods of prior art have the shortcomings of low efficiency and high cost, and can only be applied to a few materials. Taking magnetorheological polishing as an example, the cost of magnetorheological polishing fluid is high and magnetorheological polishing is used mainly for optical lenses.

The inventors of the present disclosure have investigated and designed a polishing system based on a non-Newtonian fluid and a polishing method thereof to specifically improve the aforementioned shortcomings of the prior art and to enhance industrial applicability.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a polishing system based on a non-Newtonian fluid and the polishing method thereof to address the aforementioned limitations of the prior art.

To this end, a polishing system based on a non-Newtonian fluid has been devised, which includes a polishing device, a non-Newtonian fluid auxiliary device, and a control device. The polishing device is configured to move a work piece in a polishing container, where the polishing container contains non-Newtonian fluid, and the non-Newtonian fluid has abrasives therein that causes the polishing action. The non-Newtonian fluid auxiliary device is configured to manipulate the viscosity of the non-Newtonian fluid through variation in the pressure or speed thereof, or through variation in the vibration or ultrasonic frequency applied thereto, such that the abrasives polish the work piece. The control device is used to control the polishing device to move the work piece inside the polishing container. When the non-Newtonian fluid auxiliary device is in operation, the viscosity of the non-Newtonian fluid increases, resulting in fluid characteristics resembling those of a semi-solid substance. When the non-Newtonian fluid auxiliary device is not in operation, the non-Newtonian fluid quickly reverts to its liquid like state.

Preferably, the non-Newtonian fluid may be made of biodegradable material and the apparent viscosity of the non-Newtonian fluid may be between 20 kPa·s (Pascal second) and 100 kPa·s.

Preferably, the present invention may further include a polishing fluid circulation device, which includes a polishing container, a drainage module, a cleaning module, and a fluid feeding module. The drainage module is connected with the polishing container to discharge the non-Newtonian fluid from the polishing container. The cleaning module is installed in the polishing container to clean the polishing container and the work piece before or after the polishing. The fluid feeding module is connected with the polishing container to supply the non-Newtonian fluid to the polishing container.

Preferably, the present invention can further include a measuring device, itself including a fluid level measuring module, a viscosity measuring module, a temperature measuring module, a flow rate and velocity measuring module, and a pressure measuring module. The fluid level measuring module measures the level of the non-Newtonian fluid level in the polishing container; the viscosity measuring module measures the viscosity of the non-Newtonian fluid in the polishing container; the temperature measuring module measures the temperature of the non-Newtonian fluid in the polishing container; the flow rate and velocity measuring module measures the flow rate and velocity of the non-Newtonian fluid in the polishing container; and the pressure measuring module measures the pressure of the non-Newtonian fluid in the polishing container.

Preferably, the polishing device includes a shaft and a holding tool, wherein the shaft has a plurality of degrees of freedom in its movement. The holding tool is rotatably connected to the shaft. The holding tool is configured to hold the work piece. The control device controls the rotating speed and movement of the shaft, together with the rotating speed and angle of the holding tool.

A polishing method is also devised, including the following steps: providing a polishing container containing the non-Newtonian fluid, where the non-Newtonian fluid has abrasives therein that causes the polishing action; using a polishing device to hold a work piece and to place the work piece in the polishing container filled with the non-Newtonian fluid; using a non-Newtonian fluid auxiliary device to manipulate the viscosity of the non-Newtonian fluid by varying the pressure, speed, vibration or ultrasonic frequency, such that the abrasives polish the work piece; and using a control device to control the polishing device to move the work piece inside the polishing container. When the non-Newtonian fluid auxiliary device is in operation, the viscosity of the non-Newtonian fluid increases, resulting in fluid characteristics resembling those of a semi-solid substance. When the non-Newtonian fluid auxiliary device is not in operation, the non-Newtonian fluid quickly reverts to its liquid like state.

Preferably, the present invention can further include the following step: making the non-Newtonian fluid from biodegradable components, wherein the apparent viscosity of the non-Newtonian fluid is between 20 kPa·s and 100 kPa·s.

Preferably, the present invention further includes the following steps: connecting a drainage module to the polishing container to discharge the non-Newtonian fluid from the polishing container; installing a cleaning module in the polishing container to clean the polishing container and the work piece before or after the polishing; and connecting a fluid feeding module to the polishing container to supply the non-Newtonian fluid to the polishing container.

Preferably, the present invention can further include the following steps: measuring the level of the non-Newtonian fluid level in the polishing container, so that the level of non-Newtonian fluid in the polishing container corresponds to the work piece; measuring the viscosity of the non-Newtonian fluid in the polishing container; measuring the temperature of the non-Newtonian fluid in the polishing container; measuring the flow rate and the velocity of the non-Newtonian fluid in the polishing container; and measuring the pressure of the non-Newtonian fluid in the polishing container.

Preferably, the present invention further includes the following steps: providing a shaft which has a plurality of degrees of freedom in its movement; rotatably connecting a holding tool to the shaft; using the holding tool to hold the work piece; employing the control device to control the rotating speed and the movement of the shaft; and employing the control device to control the rotating speed and angle of the holding tool.

The polishing system based on a non-Newtonian fluid and the polishing method thereof of the present invention has one or more of the following advantages:

(1) The polishing system based on a non-Newtonian fluid and the polishing method thereof of the present invention can polish work pieces of all kinds of materials and shapes, and is especially suited to polish work piece with any 3D surfaces, such as curved surfaces, or contoured surfaces. By incorporating digital control technology for the precise coordination of the polishing process, every surface of a 3D object is subjected to the same degree of surface removal and to the same surface treatment, resulting in a uniform surface finish.

(2) The polishing system based on a non-Newtonian fluid and the polishing method thereof of the present invention may be applied to the precise polishing of optical lenses that require a high grade surface finish, as well as the rapid polishing of objects to mass produce a consistent surface finish and therefore appearance for the finished product, such as with mobile phones cases.

(3) The polishing system based on a non-Newtonian fluid and the polishing method thereof of the present invention uses a kind of non-Newtonian fluid made of environmental-friendly and biodegradable material. The waste fluid may be biodegraded, and this method of disposal is better for the environmental, uses less energy, and costs less than other disposal methods.

(4) The polishing system based on a non-Newtonian fluid and the polishing method thereof of the present invention makes use of the properties of non-Newtonian fluids. The use of a non-Newtonian fluid allows for a non-contact polishing method without the need to use grinding tools, such as abrasive disks and polishing pads. Polishing methods using such grinding tools are more costly and can cause defects, such as scratches and cuts on the work piece, when the grinding tool accidentally comes into contact with the work piece.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the first embodiment of the polishing system based on a non-Newtonian fluid of the present invention.

FIG. 2 is a schematic diagram of the first embodiment of the polishing system based on a non-Newtonian fluid of the present invention.

FIG. 3 is a block diagram of the second embodiment of the polishing system based on a non-Newtonian fluid of the present invention.

FIG. 4 is a schematic diagram of the second embodiment of the polishing system based on a non-Newtonian fluid of the present invention.

FIG. 5 is a first flowchart of the polishing method based on a non-Newtonian fluid of the present invention.

FIG. 6 is a second flowchart of the polishing method based on a non-Newtonian fluid of the present invention.

FIG. 7 is a third flowchart of the polishing method based on a non-Newtonian fluid of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

To illustrate and explain the novel features, contents, and advantages of the present invention, and the effect that can be achieved therefrom; detailed descriptions of the preferred embodiments of the present invention are herein provided, and these reference the accompanying diagrams. It should be noted, however, that the diagrams and exemplary embodiments herein used, are for the purpose of illustrating and explaining the specification of the present invention, without necessarily implying the actual size, ratio, or precise configuration. Therefore, in the accompanying diagrams, the size, ratio and configuration shall not be interpreted in any way that limits the scope, applicability or configuration of the present invention.

The following embodiments of the polishing system based on a non-Newtonian fluid and the polishing method thereof of the present invention are explained with reference to the accompanying figures. For the sake of clarity, similar elements in the embodiments described below are designated with similar numerals throughout the present disclosure.

Please refer to FIGS. 1 and 2 which are, respectively, the block diagram and schematic diagram of the first embodiment of the polishing system based on the non-Newtonian fluid of the present invention. A polishing system 100 based on the non-Newtonian fluid of the present invention is capable of polishing the surface of a work piece 9 that has various 3D surfaces, curved surfaces, or contoured surfaces. The work piece 9 can be an optical lens or the casing of consumer electronics, such as the casing of a mobile phone. The polishing system 100 includes a polishing device 10, a non-Newtonian fluid auxiliary device 20, a control device 30, and a measuring device 40. The polishing device 10 includes a shaft 11 and a holding tool 12. The shaft 11 has a plurality of degrees of freedom in its movement, such as the degrees of freedom of moving forward and backward, left and right, up and down or rotating. The holding tool 12 is connected to the shaft 11, and is able to rotate. The holding tool 12 may be a device that is capable of securing the work piece 9, e.g. a three prong clamp, or any other devices known to a person skill in the art that have equivalent capability. The holding tool 12 is configured to hold the work piece 9 firmly. In other words, during operation, the work piece 9 moves together with the shaft 11, as well as moving together with the holding tool 12 in an epicyclic motion. The polishing device 10 utilizes the shaft 11 and the holding tool 12 to drive the movement of the work piece 9 in a polishing container 51 containing non-Newtonian fluid 511. The non-Newtonian fluid 511 has abrasives 512 therein that causes the polishing action. The non-Newtonian fluid auxiliary device 20 is connected with the polishing container 51, and manipulates the viscosity of the non-Newtonian fluid 511 through variation in the pressure or speed thereof, or through variation in the vibration or ultrasonic frequency applied thereto, such that the work piece 9 is polished by the abrasives 512. The control device 30 is configured to control the polishing device 10 to move the work piece 9 inside the polishing container 51. The measuring device 40 includes a viscosity measuring module 41. The viscosity measuring module 41 measures the viscosity of the non-Newtonian fluid 511 in the polishing container 51.

After the polishing device 10 has placed the work piece 9 into the polishing container 51, the control device 30 may set and control the polishing parameters based on the material and size of the work piece 9 and the polishing grade required. For instance, a number of polishing modes and polishing duration can be preset, wherein the polishing parameters for each polishing mode may include the rotating speed and movement of the shaft 11, as well as the angle, rotating speed, movement and vertical position of the work piece 9. That is to say, the control device 30 controls the rotating speed and movement of the shaft 11, as well as the rotating speed and angle of the holding tool 12. When the polishing device 10 is in operation, the viscosity measuring module 41 of the measuring device 40 may measure the viscosity of the non-Newtonian fluid 511 in the polishing container 51, and then transmit the measured result to the non-Newtonian fluid auxiliary device 20. Based on the measured viscosity of the non-Newtonian fluid 511, the non-Newtonian fluid auxiliary device 20 manipulates the viscosity of the non-Newtonian fluid 511 through variation in the pressure or speed thereof, or through variation in the vibration or ultrasonic frequency applied thereto, such that the work piece 9 is polished by the abrasives 512.

When the non-Newtonian fluid auxiliary device 20 is in operation, the viscosity of the non-Newtonian fluid 511 resembles that of a semi-solid substance. When the non-Newtonian fluid auxiliary device 20 is not in operation, the non-Newtonian fluid 511 quickly reverts to liquid like state. With the aforementioned configuration, the abrasives 512 are able to polish the work piece 9.

Please refer to FIGS. 3 and 4 which are, respectively, the block diagram and schematic diagram of the second embodiment of the polishing system based on the non-Newtonian fluid of the present invention. In this embodiment, elements with the same numerals have the same configurations as those in the first embodiment, so their details will not be repeated here.

As shown in FIGS. 3 and 4, the polishing system 100 can further include a polishing fluid circulation device 50, itself including a polishing container 51, a drainage module 52, a cleaning module 53, and a fluid feeding module 54. The drainage module 52 is connected to the polishing container 51 through piping to discharge the non-Newtonian fluid 511 from the polishing container 51 at the proper time or when needed (for example, after polishing). The cleaning module 53 is installed in the polishing container 51 to clean the polishing container 51 and the work piece 9 before or after the work piece 9 is polished. The cleaning module 53 may, for example, include a nozzle and other elements, and may employ any cleaning method known to a person skilled in the art. The fluid feeding module 54 is connected to the polishing container 51 through piping to supply the non-Newtonian fluid 511 into the polishing container 51. The drainage module 52 and the fluid feeding module 54 may, for example, include pumps, the piping and other elements, to drain or feed the fluid.

The measuring device 40 may further include a fluid level measuring module 42, a temperature measuring module 43, a flow rate and velocity measuring module 44, and a pressure measuring module 45. The fluid level measuring module 42 measures the level of the non-Newtonian fluid 511 in the polishing container 51. The fluid level measuring module 42 ensures or confirms that the level of the non-Newtonian fluid 511 is higher than the vertical position of the work piece 9, such that the work piece 9 is completely immersed in the non-Newtonian fluid 511. The temperature measuring module 43 measures the temperature of the non-Newtonian fluid 511 in the polishing container 51; the flow rate and velocity measuring module 44 measures the flow rate and the velocity of the non-Newtonian fluid 511 in the polishing container 51; and the pressure measuring module 45 measures the pressure of the non-Newtonian fluid 511 in the polishing container 51.

In short, the polishing fluid circulation device 50 can automatically and conveniently clean the polishing container 51 and the work piece 9, in addition to replace the non-Newtonian fluid 511 and control the volume thereof.

Before or after the polishing process, the polishing fluid circulation device 50 can clean the polishing container 51 and the work piece 9 by using the cleaning module 53. During the polishing process, the polishing fluid circulation device 50 may supply the fluid through the fluid feeding module 54 based on the feedback information from the fluid level measuring module 42 at any time in order to meet the desired characteristics of the non-Newtonian fluid 511. After the non-Newtonian fluid 511 has been used for a specified number of times, the non-Newtonian fluid 511 (the polishing fluid) can be replaced through the use of the drainage module 52 and the fluid feeding module 54.

In addition, with the temperature measuring module 43, the flow rate and velocity measuring module 44, and the pressure measuring module 45 of the present invention, the flow rate, velocity, and pressure of the non-Newtonian fluid 511 can be monitored or adjusted in order to more accurately and conveniently control the non-Newtonian fluid 511 to reach the desired viscosity for polishing.

Please refer to FIG. 5 which is the first flowchart of the polishing method based on the non-Newtonian fluid of the present invention. As shown in the diagram, the polishing method based on the non-Newtonian fluid of the present invention includes the following steps: (S51) providing a polishing container containing the non-Newtonian fluid, wherein the non-Newtonian fluid includes abrasives; (S52) using a polishing device to hold a work piece and to place the work piece in the polishing container containing the non-Newtonian fluid; (S53) providing a non-Newtonian fluid auxiliary device, so that the non-Newtonian fluid auxiliary device can be used to manipulate the viscosity of the non-Newtonian fluid through variation in the pressure or speed thereof, or through variation in the vibration or ultrasonic frequency applied thereto; (S54) using a control device to control the polishing device to move the work piece inside the polishing container, so that the abrasives can polish the work piece.

Please refer to FIG. 6 which is the second flowchart of the polishing method based on the non-Newtonian fluid of the present invention. As shown in the diagram, the polishing method based on the non-Newtonian fluid of the present invention can further include the following steps: (S61) connecting a drainage module to the polishing container to discharge the non-Newtonian fluid from the polishing container; (S62) installing a cleaning module in the polishing container so that the cleaning module can be used to clean the polishing container and the work piece before or after the polishing; and (S63) connecting a fluid feeding module to the polishing container to supply the non-Newtonian fluid to the polishing container.

Please refer to FIG. 7 which is the third flowchart of the polishing method based on the non-Newtonian fluid of the present invention. As shown in the diagram, the polishing method based on the non-Newtonian fluid of the present invention can further include the following steps: (S71) measuring the level of the non-Newtonian fluid level in the polishing container, so that the level of the non-Newtonian fluid in the polishing container corresponds to the vertical position of the work piece; (S72) measuring the viscosity of the non-Newtonian fluid in the polishing container; (S73) measuring the temperature of the non-Newtonian fluid in the polishing container; (S74) measuring the flow rate and the velocity of the non-Newtonian fluid in the polishing container; and (S75) measuring the pressure of the non-Newtonian fluid in the polishing container.

The detailed explanation of the polishing method based on the non-Newtonian fluid of the present invention has been presented in the aforementioned explanation of the polishing system based on the non-Newtonian fluid of the present invention, and so their details will not be repeated here. It is worth mentioning that, a carrier liquid formulated with biodegradable ingredients, such as corn, amylum, Konjac glucomannan or cellulose, which exhibits non-Newtonian properties, may serve as the non-Newtonian fluid of the present invention; wherein the apparent viscosity of the non-Newtonian fluid is preferably between 20 kPa·s (Pascal second) and 100 kPa·s, and after the polishing process, the waste fluid may be disposed of through bio-degradation.

In a practical embodiment, the implementation steps are briefly explained here, it includes: selecting the type of abrasives according to the material and the requirements of the work piece to be polished and formulating the polishing fluid by blending the abrasives with the non-Newtonian fluid based carrier fluid; holding the work piece to be polished with the holding tool; pouring the polishing fluid into the polishing container, until the polishing liquid reaches a predetermined level; selecting the modes and the duration of polishing; setting the vertical position of the shaft, the rotating speed and movement of the shaft, as well as the rotating speed and angle of the work piece in each mode; enabling the measuring device to detect the viscosity, temperature, etc. of the non-Newtonian fluid; starting the polishing process; based on the feedback information from the measuring device, enabling the non-Newtonian fluid auxiliary device to manipulate viscosity of the non-Newtonian fluid by selectively applying vibration, pressure, ultrasonic wave, etc., so as to reach a desired viscosity; and, after the polishing process, cleaning the device.

The present invention provides a polishing method based on the non-Newtonian fluid that is suitable for processing, with high efficiency, work pieces of any shape and thus addresses the limitations of the polishing methods of prior art. The limitations of the polishing methods of prior art, as already mentioned herein, are inability to process objects with certain 3D shapes, low process efficiency and issues in waste fluid disposal. The polishing system based on a non-Newtonian fluid and the polishing method based on a non-Newtonian fluid may also include the disposal of the waste fluid through bio-degradation. The basic approach of the present invention is by: employing a carrier liquid formulated with biodegradable ingredients, such as corn, amylum, Konjac glucomannan or cellulose, which exhibits non-Newtonian properties; incorporating a device suitable for operating the non-Newtonian fluid for polishing; and taking advantage of the properties of non-Newtonian fluids that their viscosity increases when their pressure or velocity changes. In this way the operation of non-contact polishing can be carried out on the work piece.

The aforementioned description is for the purpose of illustration only and shall not be interpreted in any way to limit the scope, applicability or configuration, of the present invention. A person skilled in the art may carry out many changes and modifications as alternative embodiments, without departing from the spirit and scope of the present invention, which is intended to be limited only by the appended claims. 

What is claimed is:
 1. A polishing system based on a non-Newtonian fluid, comprising: a polishing device configured to move a work piece in a polishing container containing the non-Newtonian fluid, the non-Newtonian fluid comprising abrasives; a non-Newtonian fluid auxiliary device configured to manipulate viscosity of the non-Newtonian fluid through variation in pressure or speed thereof, or through variation in vibration or ultrasonic frequency applied thereto, such that the work piece is polished by the abrasives; and a control device configured to control the polishing device to move the work piece inside the polishing container; wherein when the non-Newtonian fluid auxiliary device is in operation, the viscosity of the non-Newtonian fluid increases, resulting in characteristics resembling those of a semi-solid substance; and when the non-Newtonian fluid auxiliary device is not in operation, the non-Newtonian fluid quickly reverts to liquid-like state.
 2. The polishing system based on the non-Newtonian fluid of claim 1, wherein the non-Newtonian fluid is made of biodegradable materials and apparent viscosity of the non-Newtonian fluid is between 20 kPa·s and 100 kPa·s.
 3. The polishing system based on the non-Newtonian fluid of claim 1, further comprising a polishing fluid circulation device, itself comprising the polishing container, a drainage module, a cleaning module, and a fluid feeding module, wherein the drainage module is connected with the polishing container to discharge the non-Newtonian fluid from the polishing container; the cleaning module is installed in the polishing container to clean the polishing container and the work piece before or after polishing; and the fluid feeding module is connected with the polishing container to supply the non-Newtonian fluid to the polishing container.
 4. The polishing system based on the non-Newtonian fluid of claim 1, further comprising a measuring device, itself comprising a fluid level measuring module, a viscosity measuring module, a temperature measuring module, a flow rate and velocity measuring module, and a pressure measuring module, wherein the fluid level measuring module measures a level of the non-Newtonian fluid in the polishing container; the viscosity measuring module measures the viscosity of the non-Newtonian fluid in the polishing container; the temperature measuring module measures temperature of the non-Newtonian fluid in the polishing container; the flow rate and velocity measuring module measures flow rate and velocity of the non-Newtonian fluid in the polishing container; and the pressure measuring module measures the pressure of the non-Newtonian fluid in the polishing container.
 5. The polishing system based on the non-Newtonian fluid of claim 1, wherein the polishing device comprises a shaft and a holding tool, the shaft has a plurality of degrees of freedom in movement thereof; the holding tool is rotatably connected with the shaft; the holding tool is configured to hold the work piece; and the control device is configured to control rotating speed and the movement of the shaft, as well as rotating speed and the angle of the holding tool.
 6. A polishing method based on a non-Newtonian fluid, comprising the following steps: providing a polishing container containing the non-Newtonian fluid, wherein the non-Newtonian fluid comprising abrasives; using a polishing device to hold a work piece and to place the work piece in the polishing container containing the non-Newtonian fluid; providing a non-Newtonian fluid auxiliary device, to manipulate viscosity of the non-Newtonian fluid through variation in pressure or speed thereof, or through variation in vibration or ultrasonic frequency applied thereto; and using a control device to control the polishing device to move the work piece inside the polishing container, such that the abrasives polish the work piece; wherein when the non-Newtonian fluid auxiliary device is in operation, the viscosity of the non-Newtonian fluid increases, resulting in characteristics resembling those of a semi-solid substance; and when the non-Newtonian fluid auxiliary device is not in operation, the non-Newtonian fluid quickly reverts to liquid-like state.
 7. The polishing method based on the non-Newtonian fluid of claim 6, further comprising the following steps: making the non-Newtonian fluid from biodegradable materials, wherein apparent viscosity of the non-Newtonian fluid is between 20 kPa·s and 100 kPa·s.
 8. The polishing method based on the non-Newtonian fluid of claim 6, further comprising the following steps: connecting a drainage module to the polishing container to discharge the non-Newtonian fluid from the polishing container; installing a cleaning module in the polishing container to clean the polishing container and the work piece before or after polishing; and connecting a fluid feeding module to the polishing container to supply the non-Newtonian fluid to the polishing container.
 9. The polishing method based on the non-Newtonian fluid of claim 6, further comprising the following steps: measuring a level of the non-Newtonian fluid in the polishing container, so that the level of the non-Newtonian fluid in the polishing container corresponds to the work piece; measuring the viscosity of the non-Newtonian fluid in the polishing container; measuring temperature of the non-Newtonian fluid in the polishing container; measuring flow rate and velocity of the non-Newtonian fluid in the polishing container; and measuring pressure of the non-Newtonian fluid in the polishing container.
 10. The polishing method based on the non-Newtonian fluid of claim 6, further comprising the following steps: providing a shaft having a plurality of degrees of freedom in movement thereof; connecting a holding tool to the shaft, wherein the holding tool is rotatably connected to the shaft; using the holding tool to hold the work piece; employing the control device to control rotating speed and movement of the shaft; and employing the control device to control rotating speed and angle of the holding tool. 